Rotary fan.



H. N. SEARLES.

ROTARY FAN.

APPLICATION FILED NOV. 24. 19H.

Patented July 9, 1918.

A TTOHIVEY,

ROTARY FAN.

Specification of Letters Patent.

Patented July 9, Edith.

Application filed November 24, 1917. Serial No. 203,669.

To all whom it may concern Be it known that l, HERBERT N. SEAnLns, a citizen of the United States, and a resident of the borough of Manhattan, city county, and State of New York, have invented a new and useful Improvement in Rotary Fans, of which the following is a specification.

It is the purpose of this invention to so construct the fan that its efiiciency, diameter and speed of rotation considered, will be materially increased, so that where there is a given amount of air circulation required for the accomplishment of a desired result, a fan of smaller size than heretofore and driven at a less speed than heretofore will serve the purpose. Consequently, of course, fans embodying my construction, of whatever diameter they may be and driven at whatever speed, will be more efficient than those of the same diameter and speed as heretofore constructed.

Generally stated, I accomplish the desired results by making the blades of the fan of substantially equal width throughout, and by. producing uponthe rear edge of each blade a forwardly curving or inclined flange of substantially equal width throughout, the inner or hub end of the flange being curved inwardly toward the hub of the fan, thus forming at the hub end of each blade a semi-bowl-shaped forwardly presented part, which not only prevents the escape of air around the inner end of the blade, but also forcibly ejects it forward, with the result that owing to the increased width of the blades, the continuously extending flange having substantially equal width throughout, and the bowlsshaped central terminal of each flange, a concent-ration and forward projection of the air blast are efiected, somewhat after the fashion of an air jet from the mouth or delivery spout of a blower. The suction or flow of air to the'fan is likewise improved.

Referring 'to the drawings, Figure 1 is an elevation, taken from the front, of a fan embodying my invention; Fig. 2 is an edgewise elevation of the fan shown in Fig. 1.

In the drawings 1 represents the hub of the fan. It may be of any construction. 2 is a metallic spider frame shown in the present instance as having four arms, one for each blade. The arms are fashioned at such an angle as to properly support the blades. 3, 3, are bolts, rivets, or screws, as the case may be, whereby the blades 4, d, are fastened to the arms of the spider frame 2. It will be noted, by reference to Fig. 1, that the blades are of substantially equal width throughout and upon the rear edge of each blade 1 form a flange 5, which extends along its rear edge, and at the inner or hub end each flange curves inwardly toward the hub, as shown at 6, 6, abutting against the hub, thus forming a semi-bowlshaped part at that end, in which the air, as indicated by the arrows, is turned and projected forwardly and prevented from escaping around the inner end of the blades.

in this Fig. 1 of the drawings the circumferentially arranged arrows indicate the direction in which the fan revolves, and the shorter arrows indicate the direction of the air drafts under the act-ion of the flanges. The fine lines which cross each other at the axis of the hub are intended to indicate generally about the line on each blade at which the curvature or forward inclination of the flange commences. There is nothing arbitrary about this, however. The area relation between the plane or flat part of each blade as compared with the forwardly inclined or flange part thereof may be such as preferred; but whatever that relation may be, the flange should be continuous along substantially the entire rear edge of each blade, and its central or hub end should curve inwardly to form the semi-bowlshaped part above referred to.

The operation of fans of this construction is peculiarly satisfactory; owing to the substantially equal width of each blade practically all the air within the area of their revolution is controlled by them, and under the action of the continuous extending flanges, and particularly of the centrally located bowl-shaped terminals thereof, the air is forcibly projected forwardly in much greater volume and with much greater force than in any fan known to me, so that l am enabled to use a fan of my construction in places where the space is restricted and yet high eficiency required, as, for instance, in automobiles, motor boats, and the like. Furthermore, many experiments have demonstrated the fact that the increased width of the blades and the extended length and width of the flanges and the bowlshaped inner terminals thereof, induce a very pronounced air suction toward the fan from all the surrounding area, thus tending to increase the supply to be projected forwardly through what may be called the blast area of the fan.

I do not limit myself to the details of construction described and shown because it will be obvious to those familiar with such matters that certain changes may be made in the details and yet the essentials of my invention be employed.

I claim:

1. A fan the blades whereof are of substantially equal width throughout, each having a sharp, unobstructed forward edge, the forward part of each blade being substantially flat and the rear edge of each blade having a laterally projecting flange of substantially equal width throughout and which extends to the hub of the fan.

2. A fan each of the blades whereof has a thin and unobstructed forward edge, a substantially flat forward'part and a laterally projecting flange on its rear edge, the

inner end of each flange being brought foryfvardly and inwardly against the hub of the 3. A fan the blades whereof are of substantially equal width and flat in their forward part terminating in thin and unobstructed forward edges and at their inner or hub end a forwardly projecting semibowl-like flange upon their rear edge which abuts against the hub.

4. A fan each blade whereof is of substantially equal width throughout and flat in its forward part terminating in a thln and unobstructed forward edge and having on its rear edge a longitudinally extending and laterally projecting flange of substantially equal depth throughout, the inner or hub end of each flange being turned inwardly and formed into a semi-bowl-like part resting against the hub.

In testimony whereof I have signed my name to this specification. v HERBERT. N. SEARLES. 

